Belt type continuous variable transmission, power unit having the belt type continuous variable transmission, vehicle mounting thereon the belt type continuous variable transmission, and sheave for continuous variable transmission

A belt type continuous variable transmission comprising:

• a primary sheave that outputs torque,
• a secondary sheave that receives torque from the primary sheave, and
• a belt entrained between the primary sheave and the secondary sheave in an endless manner to transmit torque to the secondary sheave from the primary sheave, wherein
• the primary sheave comprises:
• a first sheave body,
• a second sheave body provided to be relatively slidable in a direction toward and away from the first sheave body and forming between the second sheave body and the first sheave body a belt groove, about which the belt is entrained,
• a plurality of push bodies that rotate together with the second sheave body and move radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, such movements causing the second sheave body to slide to change a diameter, at which the belt is entrained about the primary sheave, and
• a plurality of stoppers that restrict movements of the push bodies by contacting with outer surfaces of the push bodies when the second sheave body reaches a position of minimum transmission gear ratio, in which a diameter, at which the belt is entrained, is made largest, the stoppers comprising at least one projection projecting toward the outer surface of the push body, wherein
• each of the plurality of push bodies includes a roller weight and at least outer peripheries thereof are lower in hardness than the plurality of stoppers.

A belt type continuous variable transmission comprising:

• a primary sheave that outputs torque,
• a secondary sheave that receives torque from the primary sheave, and
• a belt entrained between the primary sheave and the secondary sheave in an endless manner to transmit torque to the secondary sheave from the primary sheave, wherein
• the primary sheave comprises:
• a first sheave body,
• a second sheave body provided to be relatively slidable in a direction toward and away from the first sheave body and forming between the second sheave body and the first sheave body a belt groove, about which the belt is entrained,
• a plurality of roller weights that rotate together with the second sheave body and move radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, such movements causing the second sheave body to slide to change a diameter, at which the belt is entrained about the primary sheave, and
• a plurality of stoppers that restrict movements of the roller weights by contacting with outer surfaces of the roller weights when the second sheave body reaches a position of minimum transmission gear ratio, in which a diameter, at which the belt is entrained, is made largest, the stoppers comprising a plurality of projections projecting toward the outer surface of the roller weight, the projections being spaced from each other in an axial direction of the roller weight, wherein
• at least outer peripheries of the plurality of roller weights are lower in hardness than the plurality of stoppers.

A belt type continuous variable transmission comprising:

• a primary sheave that outputs torque,
• a secondary sheave that receives torque from the primary sheave, and
• a belt entrained between the primary sheave and the secondary sheave in an endless manner to transmit torque of the primary sheave to the secondary sheave, wherein
• the primary sheave comprises:
• a first sheave body,
• a second sheave body provided to be relatively slidable in a direction toward and away from the first sheave body and forming between the second sheave body and the first sheave body a belt groove, about which the belt is entrained,
• a plurality of push bodies that rotate together with the second sheave body and move radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, such movements causing the second sheave body to slide to change a width of the belt groove, and
• a plurality of stoppers that restrict movements of the push bodies when the second sheave body reaches a position of minimum transmission gear ratio, in which the belt groove is made smallest in width, the stoppers comprising a first contact portion that contacts with the push body when the second sheave body reaches the position of minimum transmission gear ratio, and a second contact portion positioned outside of the first contact portion radially of the second sheave body, the first contact portion being lower in hardness than the push bodies and the second contact portion.

A power unit comprising:

• a drive source, and
• a belt type continuous variable transmission interlocking with the drive source, the belt type continuous variable transmission comprising:
• a primary sheave that outputs torque transmitted from the drive source,
• a secondary sheave that receives torque from the primary sheave, and
• a belt entrained between the primary sheave and the secondary sheave in an endless manner to transmit torque to the secondary sheave from the primary sheave, wherein
• the primary sheave comprises:
• a first sheave body,
• a second sheave body provided to be relatively slidable in a direction toward and away from the first sheave body and forming between the second sheave body and the first sheave body a belt groove, about which the belt is entrained,
• a plurality of push bodies that rotate together with the second sheave body and move radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, such movements causing the second sheave body to slide to change a width of the belt groove, and
• a plurality of stoppers that restrict movements of the push bodies by contacting with outer surfaces of the push bodies when the second sheave body reaches a position of minimum transmission gear ratio, in which the belt groove is made smallest in width, the stoppers being shaped to accelerate partial wear of the outer surfaces of the push bodies, wherein
• each of the plurality of push bodies includes a roller weight and at least outer peripheries thereof are lower in hardness than the plurality of stoppers.

A vehicle comprising:

• a frame,
• a drive source supported on the frame, and
• a belt type continuous variable transmission interlocking with the drive source, the belt type continuous variable transmission comprising:
• a primary sheave that outputs torque transmitted from the drive source,
• a secondary sheave that receives torque from the primary sheave, and
• a belt entrained between the primary sheave and the secondary sheave in an endless manner to transmit torque to the secondary sheave from the primary sheave, wherein
• the primary sheave comprises:
• a first sheave body,
• a second sheave body provided to be relatively slidable in a direction toward and away from the first sheave body and forming between the second sheave body and the first sheave body a belt groove, about which the belt is entrained,
• a plurality of push bodies that rotate together with the second sheave body and move radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, such movements causing the second sheave body to slide to change a width of the belt groove, and
• a plurality of stoppers that restrict movements of the push bodies by contacting with outer surfaces of the push bodies when the second sheave body reaches a position of minimum transmission gear ratio, in which the belt groove is made smallest in width, the stoppers being shaped to accelerate partial wear of the outer surfaces of the push bodies, wherein
• each of the plurality of push bodies includes a roller weight and at least outer peripheries thereof are lower in hardness than the plurality of stoppers.

A sheave for continuous variable transmissions, comprising:

• a first sheave body,
• a second sheave body that forms between the second sheave body and the first sheave body a belt groove, about which a belt is entrained,
• the second sheave body being enabled by a push body, which moves radially of the second sheave body according to centrifugal forces generated at the time of rotation of the second sheave body, to relatively slide in a direction toward and away from the first sheave body, and comprising:
• a stopper that restricts movements of the push body by contacting with an outer surface of the push body when slid to a position of minimum transmission gear ratio, in which the belt groove is made smallest in width, the stopper being shaped to accelerate partial wear of the outer surface of the push body, wherein
• the push body includes a roller weight and at least an outer periphery thereof is lower in hardness than the stopper.